题目

Sometimes I really doubt whether there is love between my parents．Every day they are very busy trying to __1__ in order to pay the high tuition for my brother and me．They don't act in the  __2__ ways that I read in books or I see on TV．In their opinion, I love you is too _3__ for them to say．Sending flowers to each other on Valentine's Day is even more out of __4__．One day, my mother was sewing a quilt．I sat down beside her．Mom, I have a question to ask you．Is there _5__ between you and Dad? I asked her in a very low voice．She didn't answer immediately．She __6__ her head a两块大小、形状完全相同的金属平板平行放置，构成以平行板电容器，与它相连接的电路如图所示，接通开关K，电源即给电容器充电（ ）A．保持K接通，减小两极板间的距离，则两极板间电场的电场强度减小B．保持K接通，在两极板间插入一块介质，则极板上的电量增大C．断开K，减小两极板间的距离，则两极板间的电势差减小D．断开K，在两极板间插入一块介质，则极板上的电势差增大